I386_IOPL(2) NetBSD/i386 System Calls Manual I386_IOPL(2)
NAMEi386_iopl -- change the i386 I/O privilege level
LIBRARY
i386 Architecture Library (libi386, -li386)
SYNOPSIS#include <sys/types.h>#include <machine/sysarch.h>inti386_iopl(int iopl);
DESCRIPTIONi386_iopl() sets the i386 I/O privilege level to the value specified by
iopl. This call is restricted to the super-user.
RETURN VALUES
Upon successful completion, i386_iopl() returns 0. Otherwise, a value of
-1 is returned and the global variable errno is set to indicate the
error.
ERRORSi386_iopl() will fail if:
[EPERM] The caller was not the super-user, or the operation was not
permitted at the current security level.
REFERENCES
i386 Microprocessor Programmer's Reference Manual, Intel
WARNING
You can really hose your machine if you enable user-level I/O and write
to hardware ports without care.
NetBSD 8.0 April 12, 2004 NetBSD 8.0

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